This section provides background information related to the present disclosure which is not necessarily prior art.
There has long been a need for joining two components in a manner that fixedly and sealingly couples the components to one another. One extremely common application concerns the coupling of copper tubing that is commonly employed to transmit potable water in a building.
Sweat soldering has long been used for the connection of components of copper based supply and distribution systems for potable water, especially in single family residential constructions, due to its durability and the relative ease with which lead-based solder connections could be made. Modern plumbing codes have mandated lead-free solders and water soluble fluxes and as such, the difficulty in making sweat solder connections has significantly increased, particularly where relatively large diameter copper tubing is utilized. More particularly, the lead-free solders and water soluble fluxes tend to be less tolerant of certain variables (e.g., the presence of oxidation and/or the use of excessive heat) than the lead-based solders and acid-based fluxes. Furthermore, sweat soldering can be relatively time consuming.
In an effort to eliminate the disadvantages of sweat solder connections, it has been proposed that a two-part epoxy be employed to adhesively couple the tubing and connectors to one another. More specifically, it is known to apply a two-part epoxy adhesive between a copper tube and a copper fitting (the copper fitting being suitable for coupling to the copper tube via traditional sweat soldering). Such epoxies have performed well in fixedly coupling components to one another but have not performed well in forming a seal between the components. Often, the sliding of the fitting onto the tubing (or the tubing into the fitting) can have the effect of scraping the epoxy off relatively small portions of the tubing and/or the fitting so that a void was formed therebetween. While the epoxy generally has sufficient strength to couple the fitting and the tubing together, the presence of the void rendered the joint unsuitable for its intended function (e.g., to communicate a fluid, such as potable water or a refrigerant therethrough without leaking).
The adhesive also has a set time period during which the tube and connector must be attached. In the plumbing industry, tubes and connectors may be stored for long periods of time before use, making an adhesive impractical to apply at any time other than at the time of use. Further, employing an adhesive renders a bond between the fitting and tubing. Therefore, in cases where it is desired to only bond the fitting and tubing by crimping, the adhesive poses a disadvantage.
Another connection process that has been proposed employs fittings that utilize internal seals wherein the fittings are crimped directly to lengths or sticks of conventional hard drawn copper tubing. Some examples include an inner o-ring seal that is carried on an inner diameter of the fitting and which sealingly engages the copper tubing upon insertion into the fitting. A crimping tool is subsequently employed to crimp the fitting to the tubing to thereby fixedly couple the tubing and the fitting to one another.
This system, however, is known to suffer from a drawback concerning the sealing of the fitting to an outside surface of the copper tubing. It is well known in the art that the outside surface of a copper tube is relatively susceptible to imperfections (e.g., gouges, scratches and the like) during its formation via extrusion as well as to damage during shipping and storage. As such imperfections and damage may adversely affect the ability of the fittings to seal against the outer surface of the tubing, manufacturers of the copper tubing typically subject the extruded sticks of tubing to an eddy current test to verify the integrity of each stick's outside surface. This testing is costly and as we have found, leaks are possible even when the tubing conforms to published standards. Accordingly, it appears that a relatively time consuming manual inspection must be made of each tube prior to its coupling to a fitting.
A third connection process involves threaded applications where a liquid sealant is applied to the threads as they are threaded on to the receiving portion. It is known in the art to apply liquid sealant to fill voids between male and female threads to make joints leak proof. The user must apply the sealant as the male threaded portion is threaded into the female threaded portion. This system faces a drawback where the user desires the sealant to be preapplied to a fitting for a later quick attachment of the fitting and tube. The liquid sealant does not hold a preapplied position, and, therefore, cannot be preapplied.
In view of the aforementioned known connection systems, there remains a need in the art for a connection system that can be used to fixedly and sealingly couple components together that is both reliable and relatively inexpensive.